Nishedha or prohibition of wrong actions is an important aspect of Hindu philosophy. The Purva Mimamsa school of philosophy holds that performance of prohibited actions is papa (demerit).
Mimamsa means inquiry, and the main objective of the system is to establish the authority of Veda, because Vedas teach dharma or religious duties. Dharma is what is enjoined in Vedas (codana-lakshano-rtah). Vedic commands are in the form of both do’s and don’ts. The positive command is called vidhi, and the negative command is nishedha (or pratisidha).
Vidhis are the main source of dharma. The positive commands, such as obligatory duties (nityakarma) and occasional rites (naimittaka karmas), are categorical imperatives. The performance of nityakarmas and naimittikakarmas does not earn any merit, but their non-performance will result in demerit. One must avoid kamya-karma (self-centered action) and prohibited karma, such as killing. By avoiding forbidden (nishedha) courses of conduct we avoid re-birth. Sacrifices will generate unseen potency (apurva) in the self till the appropriate reward is reaped. It is apurva that bridges the time-gap between a spiritual act and its fruit. One should purge oneself of all karmas, good or bad – in order to avoid rebirth.
The motive for carrying out the Vedic commands according to Bhatta Mimamsa arises from man’s desire (ishta sadhanata jnana). But Prabhakara School does not agree with this. According to it, the mandate of Veda is imperative – karyatajnanam. It is only reverence for the mandate that should serve as the motive for obeying it. However, regarding the necessity for obeying Veda, there is no difference of opinion between the two schools.